Ultrafast Capture of Aqueous Triiodide by a K+-Coordinated Crown-Ether Covalent Organic Framework
Jiyou Zhu , Ruipeng Li , Wenjuan Zhao , Hui Li , Li Zhang , Fenghua Bai , Yujie Wang , Qianrong Fang
Chinese Journal of Chemistry ›› 2026, Vol. 44 ›› Issue (14) : 2354 -2362.
Radioiodine poses severe long-term risks owing to its persistence and bioaccumulation in aquatic ecosystems, yet the rapid removal of triiodide (I3–), the most stable iodine species in water, remains a fundamental challenge. Here, we report JUC-725@K+, a two-dimensional K+-coordinated crown-ether covalent organic framework (COF), in which the ordered confinement of K+ within the crown-ether domains markedly enhances the framework's affinity for ultrafast I3– capture. Driven by the synergistic effects of ion fixation, solvation suppression, and enhanced binding energy, JUC-725@K+ achieves 99% I3– removal within 6 min, with an exceptional apparent adsorption rate constant of 16.5 g·g–1·min–1, outperforming all previously reported porous iodine adsorbents. High removal efficiency above 97% is maintained under continuous-flow conditions, highlighting the robustness of the material. Meanwhile, K+ incorporation greatly improves interfacial hydrophilicity, accelerating aqueous mass transport. Density functional theory further confirms that K+ confinement strengthens I3– binding in the parent COF, establishing an ion-cooperative host-guest chemistry for scalable radioiodine capture.
Covalent organic framework / Crown ether / Iodine adsorption / Metal coordination / Triiodide ion
2026 SIOC, CAS, Shanghai, & WILEY-VCH GmbH
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